Abstract
This study attempted to clarify diSessa & Cobb's "Ontological Innovation", a new perspective on theorization of practices in design-based research at United States, and examined the suggestions for future studies about theorization of practices in Japanese research of educational methods, as obtained from study of the "Ontological Innovation" perspective. First of all, I outlined the current state of theorization of practices in the design-based research of the United States. It was focused on discussion about the base of theorization and the type of theories in design-based research. Second, according to diSessa & Cobb, I examined of the "Ontological Innovation" perspective. Third, I discribed about "meta-representational competence" and "sociomathematical norms" as cases of ontological examination in some detail. Finally, on the basis of the findings detailed above, I discussed suggestions for future studies about theorization of practices in Japanese research of educational methods.
